Caring, funny and loyal. That is how friends remember the 20-year-old Velez who was fatally stabbed at a weekend party on Sherbrook Avenue.

“I am still in shock. I still feel like I am in a nightmare waiting to wake up from it,” said Mr. McKnight, 21, of Worcester.

Mr. Velez’ mother confirmed Monday that her son died from his wounds. Police confirmed that Mr. Velez was the victim of the stabbing, and said Mr. Velez died Tuesday morning at UMass Memorial Medical Center — University Campus.

Police are seeking to arrest Jay S. Anderson, 21, of 15 Calamint Hill Road North, Princeton, on charges of murder in connection with the early morning incident.

Mr. Anderson allegedly arrived at a party at 35 Sherbrook Ave. sometime Friday evening, according to a statement of facts on file in court.

“Sometime later, a verbal confrontation ensued between the victim and Mr. Anderson,” Police Sgt. Gary J. Quitadamo wrote in the statement of facts. “The argument had ended when Mr. Anderson suddenly and without warning brandished a knife, stabbed the victim in the neck, and fled the scene prior to the arrival of police.”

Police responded to a report of a large fight and stabbing at 35 Sherbrook Ave. about 1:20 a.m. Saturday and were told that a victim had been taken to an area hospital.

Mr. Anderson was still being sought by police as of Tuesday evening.

Witnesses identified Mr. Anderson as the alleged assailant in the first killing in the city this year. Police said that Mr. Anderson has three outstanding warrants, and that one for assault and battery with a dangerous weapon. Police suspect that Mr. Anderson may have shaved his head or cut his hair very short, according to police.

A friend of Mr. Velez for 10 years, Mr. McKnight saw his friend the day before Saturday’s party. Mr. Velez was doing homework at Mr. McKnight’s home. Many friends called Mr. Velez, “Bo.”

At a vigil held Tuesday night, Mr. Velez’ warmth and caring spirit and love of others was recalled by more than 50 friends and family members who gathered off Mann Street for a candelight session.

By the end of the service, more than two dozen candles lined a wall outside a Beaver Brook Park building as those attending sobbed, hugged one another and remembered a young man who enjoyed a good time and who held no ill will against others.

Mr. Velez’ brother said the outpouring of support comforted a grieving family, including his mother who briefly attended the service held in the parking lot of Beaver Brook Park. A slight dusting of snow began falling near the end of the quiet memorial as the crowd, mostly young people, huddled against the chill and wind. Some wore T-shirts under their coats featuring Mr. Velez’ name and photo.

“Hold a piece of Bo in your heart,” said one speaker. “Don’t cry; keep moving on.”

Jason Piedrasanta of Worcester said he met Mr. Velez through the Mormon Church. He recalled a time when he would see his friend wearing a suit every Sunday in church.

“It’s just too bad,” he said. “He was a peacemaker and he was trying to break up a fight when this terrible thing happened.”

Within the past few months, Mr. Velez, who wanted to be a chemist, had been working, had gotten his own car, received his GED, and began classes at Quinsigamond Community College, Mr. McKnight said.“His whole life he went through this tough guy act, but then he started changing,” Mr. McKnight said. “He’s been like a brother to me.”

Mr. McKnight was not at the party Saturday morning when Mr. Velez was stabbed twice in the neck.

Marc R. Aldana, 20, hosted the party at the apartment on Sherbrook Avenue. He said he was living there. There were roughly 25 people at the party. Alcohol was served.

Mr. Aldana was in Central District Court Tuesday and arraigned on a charge for disturbing the peace. Police said he was loud and bothering people while waiting in the emergency room at UMass Memorial Medical Center — University Campus.

“I drove him to the hospital as quick as I could,” Mr. Aldana said outside the courtroom. “I just never thought it would happen. He supposed to be there ‘til the end.”

Mr. Aldana was upset with the charge against him, saying he wasn’t loud. He was released on personal recognizance and will return to court next month.

Mr. Aldana didn’t see the attack. He heard someone at the party invited some other people. When those people arrived, Mr. Velez shook one of their hands, Mr. Aldana said.

“Ten second later he was stabbing him (Mr. Velez),” Mr. Aldana said.

Mr. Velez liked to play Xbox and hang out with his friends and was willing to try anything such as snowboarding and skateboarding, his friends said.

“He just wanted to be there for you. He was all about his family,” Mr. Aldana said. “He was doing good for himself.”

Mr. Aldana grabbed his own arm and said his friend has a tattoo that meant unity is power. That summed up Mr. Velez perfectly, Mr. Aldana said.

“He was really about people and his family,” he said, recalling a time when Mr. Velez spoke to a homeless person just to chat.

Mr. McKnight also said that Mr. Velez cared for his friends. He remembered Mr. Velez helping him building a playhouse this summer. The playhouse was for Mr. McKnight’s younger brother.

“It still feels so unreal to have someone here the other day and now gone,” Mr. McKnight said.

Anyone with information about this stabbing can send an anonymous text to the Worcester Police Department at 274637 TIPWPD and a message; can send an anonymous Web-based email to worcesterma.gov/police; or call the Worcester Detective Bureau at (508) 799-8651.